likely to positively impact practice patterns for
clinicians who perform vasectomy.
The failure rate after vasectomy with a subse-
quent risk of pregnancy after documented occlusive
success is approximately 1/2,000 cases.
has the lowest failure rate of all forms of contra-
Groups at many clinics adhere to strict
practice protocols, such that azoospermic PVSA
based on assessment of a centrifuged pellet ensures
the likelihood of sterility. Due to the variable
clearance time of residual sperm from the male
genital tract, PVSA timing, the number of PVSAs
required to achieve azoospermia and the number of
ejaculations after vasectomy do not correlate well
with the achievement of azoospermia after vasec-
For these reasons, at our andrology labo-
ratory as well as at others con±rmation of sterility
after vasectomy was de±ned as azoospermia on
2 sequential PVSAs with concurrent centrifuged
pellet analyses.
In contrast to these more conservative protocols
of post-vasectomy followup, the AUA vasectomy
guidelines de±ne vasectomy success as azoospermia
or RNMS in a single uncentrifuged PVSA, de±ned
as 100,000 or greater nonmotile sperm per ml.
criteria of azoospermia on pellet analysis, including
RNMS in the de±nition of occlusive success has the
potential to decrease the number of PVSAs, improve
the documented success rate, increase compliance
with followup and reduce the number of repeat
We determined how the less stringent 2012 AUA
vasectomy guidelines would have altered our clin-
ical practice. Accordingly, we analyzed our PVSA
data to determine whether our clinical practice
outcomes would have changed in light of the new
This study was approved by the institutional review board
for the protection of human subjects at Baylor College of
Medicine. We retrospectively reviewed the records of all
men who underwent vasectomy and returned for at least 1
PVSA from January 2000 to June 2012. All PVSA data
were analyzed. The charts of all men who were not cleared
as sterile by our institutional followup protocol were
reviewed to determine whether repeat vasectomy was
performed or unintended pregnancy occurred.
All vasectomies were performed by a single surgeon
after obtaining informed consent. The vasectomy tech-
nique was conventional vasectomy using bilateral upper
scrotal skin incisions. Intravenous sedation and local
anesthesia were used. Vasal occlusion was achieved by
placing titanium clips and removing a vasal segment.
Informed consent included the institutional policy
recommendation that the patient provide 2 sequential
PVSAs at least 1 week apart beginning 3 months after
vasectomy. A masturbatory sample was collected in the
of±ce or brought in and examined within 1 hour of
collection. No appointments were scheduled and the
patient was responsible for providing the samples.
Each PVSA was initially evaluated as a complete
semen analysis performed manually by a certi±ed
andrology laboratory technician. If the sample was
azoospermic, it was centrifuged at 200
gravity for
10 minutes for semen pellet analysis. Documentation of 2
sequential azoospermic PVSAs using a protocol requiring
analysis of the centrifuged semen pellet was used to
de±ne the occlusive success rate and patient compliance
with the post-vasectomy followup protocol of our practice.
For patients who underwent repeat vasectomy the sperm
concentration and motility was recorded from each PVSA.
To determine how the revised practice criteria based on
the 2012 AUA vasectomy guidelines would have changed
post-vasectomy outcomes, each patient was reevaluated to
assess compliance and the vasectomy occlusive success
rate as well as the need for repeat vasectomy according to
the new criteria. Since each PVSA included data on
routine manual semen analysis as well as centrifuged
pellet analysis, accurate comparison was possible between
our standard andrology laboratory protocol using centri-
fuged pellet analysis and the AUA vasectomy guidelines
using uncentrifuged semen analysis.
Time to occlusive success was determined by the days
between the ±rst PVSA and documented occlusive success
on a subsequent PVSA. Because all men were required to
wait at least 3 months before the ±rst PVSA, this time was
not calculated into the difference between the time to
clearance for the institutional protocol vs the guideline
protocol. The number of repeat PVSAs that would no
longer be considered necessary based on the revised
criteria of the guidelines, the estimated cost of any un-
needed PVSAs in men who did not achieve azoospermia
but had RNMS and the number of repeat vasectomies
were determined to ascertain the cumulative bene±t of
using the new guidelines.
We used 2-tailed z-test calculations to determine sta-
tistical signi±cance between our established andrology
laboratory de±nition and the AUA vasectomy guidelines.
Data were analyzed using Excel
and SPSS
differences considered statistically signi±cant at p
A total of 1,740 vasectomies were performed be-
tween January 2000 and June 2012. The study
cohort comprised 972 men (55.9%) who returned
to our laboratory for at least 1 PVSA. A total of
1,919 PVSAs were obtained in these men, who had a
SE age of 39.7
0.2 years. Initial PVSA
performed 3 months after vasectomy in the 972
tested men revealed that 643 (66.2%) were azoo-
spermic, 278 (28.6%) presented with RNMS, 34
(3.5%) had greater than 100,000 nonmotile sperm
per ml and 17 (1.8%) had motile sperm present in
the ejaculate (part
of ±gure). Of the 972 men who